Warfarin therapy and risk of hip fracture among elderly patients

Study Objective — To ascertain the relationship between warfarin therapy and subsequent hip fracture in a large elderly population.

Design — Retrospective, population-based cohort study.

Setting — Population-based health care administrative databases for Ontario, Canada.

Patients — Elderly patients receiving warfarin (52,701 patients), thyroid replacement therapy (40,555), an oral corticosteroid (43,915), or a proton pump inhibitor (60,383). The proton pump inhibitor group served as controls.

Measurements and Main Results — The association between warfarin therapy and subsequent hospitalization for hip fracture in elderly patients was examined by researching administrative data from January 1, 1994-March 31, 1999, for the elderly population of Ontario. Relative to patients receiving proton pump inhibitors, patients receiving warfarin (adjusted risk ratio [aRR] 0.94, 95% confidence interval [CI] 0.81–1.09) or thyroid replacement therapy (aRR 1.02, 95% CI 0.89–1.18) incurred similar risks of hip fracture. As expected, patients receiving oral corticosteroids incurred an increased risk (aRR 1.44, 95% CI 1.21–1.70) relative to patients receiving proton pump inhibitors.

Conclusion — Warfarin was not associated with increased risk of hip fracture.